This invention relates to the structures of vehicle bodies and of parts for them, and to panels for use in such structures. It relates in particular to the bodies of vehicles such as buses.
2. Description of the Prior Art
Buses are usually constructed by building an accurately-jigged frame, including a series of hoops joined by longitudinal stringers, on to a manufacturer's standard chassis. Facing panels are then attached to the frame. The frame is a large component, occupying nearly the same superficial volume as the finished bus itself, and must be very accurately made thus requiring expensive jigs and tooling. Expensive skilled labour is also required to make the frame and to fit the panels to it. Thus bus bodies made in this way are expensive. They also tend to lack rigidity unless the components of the frame are quite massive, thus adding to weight and expense.
A modification of the above construction system, known sometimes as "integral" or "semi-integral" construction, has been used for some buses. In this system chassis and frame are designed together, with the intention that each should only be used with the other. Weight for weight, the resulting body is usually more rigid than one constructed by the more customary system already described. The requirement for skilled labour to assemble the frame and fit the panels to it is also often reduced. However, the tooling cost is even higher, and because the chassis is no longer a standard item such methods of construction are usually only profitable when very long production runs can be assured.
The present invention arises from an appreciation of the advantages of making a vehicle body, ready to fit to a typical chassis, from panels of relatively few different shapes that can be mass-produced to high standards of accuracy, and from an appreciation that it is possible to make such panels so that they themselves, when assembled to make up the body, can provide it with at least a substantial part of the structural strength that it will require.